Process of degumming silk



Patented Apr. 26, 1932 UNITED STATES PATENT OFFICE LEO WALLERSTEIN, OF NEW YORK, N. Y., ASSIGNOR TO WALLERSTEIN COMPANY, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK ZEROOESS OF DEGUMMING SILK Ho Drawing.

This invention relates to certain improvevments in a process for degumming silk.

In a prior atent issued to me No. 1,644,764, dated ctober 11, 1927, I have disclosed a process for degumming silk which consists in a treatment of the silk, under suitable conditions as to temperature, etc., with a solution of a proteolytic enzyme, such as papain, which is active in an acid, in a slightly alkaline, and in a neutral medium, and in a co-pending application Serial No. 165,491 I have disclosed the treatment of such enzyme solution with an activator, such as potassium cyanide, which reduces the amount of the enzyme necessary to effect the desired degumming of the silk, and also effects a more complete and quicker action of the enzyme.

It is the especial object of the present invention to provide a process which will have the desired degumming effect on the silk, but in which an activator is employed with the enzyme solution which is substantially non-poisonous and, therefore, safe and easy to handle, and which at the same time will have the desired activating efiect on the enzyme.

I have discovered that the salts of hydrosulfurous acid, such for instance as sodium hydro-sulfite or its formaldehyde compound, sodium sulfoxylate, are activators which when used under suitable conditions as to temperature, etc., in the enzyme solution have the desired activating effect on the enzyme, but at the same time are substantially non-poisonous, so that they may be used with safety and with the desired efi'ects.

4 In carrying out my process, the silk, in

skeins or other desired or convenient form, is subjected to a preliminary washing in a weak soap solution or Weak alkaline solution. The washed silk is then immersed in a solution or bath of the selected proteolytic enzyme, as for instance papain, at a temperature of 50 C. or above, the silk, after it has Y been sufficiently degummed, being rinsed and dried.

In carrying out the process of the present invention, I add to the enzyme bath an activator in the form a salt of hydro-sulfurous Application filed January 7, 1928. Serial No. 245,263.

acid, which is substantially non-poisonous, the employment of such salt rendering the bath safe to handle and efl'ectinga decrease in the amount of the enzyme used and the desired acceleration of its action.

\Vhile various salts of hydro-sulfurous acid may be used and the conditions of use may be somewhat varied, as a specific example I may proceed as follows, using a papain solution as illustrative. The papain bath or solution is prepared in the proportion of one gram of papain of commercial strength to 5 liters of water. To this bath is added a salt of hydro-sulfurous acid, such as sodium hydrosu'lfite or its formaldehyde compound, such as sodium sulfoxylate, or both if desired. This activator is added to the bath in amounts which may vary. In actual practice, from 1 to 4 parts of the activator may be used for each part of papain, as for instance for the papain bath specified from 1 to 4 grams of the activator may be added. The whole amount of the activator may be added to the bath at once, or it may be added at different times while the degumming action of the enzyme is taking place, such procedure having been found to be of advantage under certain conditions of use.

By the use of such activator, the time of the desired degumming action of the enzyme is reduced, thus permitting faster working, and the amount of the enzyme proportionately to the amount of the silk treated may be lessened, and at the same time the activator may-be safely used and without any deleterious action on the fiber of the silk.

What I claim is:

1. The process of degumming silk which consists in subjecting the silk to the action of a proteolytic enzyme of that type which is active in a neutral, Weak alkaline, and a slightly acid medium and which is activated by the presence of a salt of hydro-sulfurous acid until the desired amount of degumming has occurred.

2. The process of degumming silk which consists in subjecting the silk to the action of a proteolytic enzyme of that type which is active in a neutral, Weak alkaline, and a 100 slightly acid medium and which is activated by the presence of a sodium salt of hydrosulfurous acid. a

3. The process of degummingsilk which consists in subjecting the silk to the action of a proteolytic enzyme of that type which is active in a neutral, weak alkaline, and a slightly acid medium and which is activated by the presence of sodium hydro-sulfite.

4. The process of degumming silk which consists in subjecting the silk to the action of a solution of papain in the presence of a salt of hydro-sulfurous acid.

5. The process of degumming silk which consists in subjecting the silk to the action of a solution of papain in the presence of a sodium salt of hydro-sulfurous acid.

6. The process of degumming silk which consists in subjecting the silk to the tuition of a solution of papain in the presence of sodium hydro-sulfite.

7. The process of degumming silk which:

consists in subjecting the silk to the action of a solution of apain in the presence of 1sodium hydro-su fite and sodium sulfoxyate.

8. The process of degumming silk which consistsin subjecting the silk in a bath or solution of papain to which has been added sodium hydro-sulfite in quantities from-1 to 4 parts by weight of the enzyme at a. temperature sufficient to maintain the activity of the enzyme.

In testimony whereof, I have hereunto set my hand.

LEO WALLERSTEIN. 

